This invention relates generally to displays for processor-based systems and appliances.
Emissive displays include light emitting devices that emit light in response to a potential. In one embodiment, each pixel may be formed of an organic light emitting device. The organic light emitting device may emit light associated with a particular color in a color gamut. Alternatively, a filter may be used to produce a desired light color.
Polymer displays or organic light emitting displays use layers of light emitting polymers. Unlike liquid crystal devices, the polymer displays actually emit light. Light emission may be advantageous for many applications.
Generally, polymer displays use at least one semiconductor conjugated polymer sandwiched between a pair of contact layers. The contact layers produce an electric field which injects charge carriers into the polymer layer. When the charge carriers combine in the polymer layer, the charge carriers decay and emit radiation in the visible range.
One semiconductive conjugated polymer that may be used in polymer displays is poly(p-phenylenevinylene) (PPV) which emits green light. Another polymer that emits red-orange light is poly(methylethylhexyloxy-p-phenylenevinylene) (MEHPPV). Other polymers of this class are also capable of emitting blue light. In addition nitrile substituted conjugated polymers may be used in forming polymer displays.
Active matrix polymer displays may be formed from a substrate such as glass or metal foil covered with an array of active elements. In one conventional structure, the active elements may be thin film transistors (TFTs). In contrast, in passive matrix displays, thin film transistors may be unnecessary. Generally, an entire column is activated at a time and row signals are then sequentially applied to that column.
In a number of cases, individual pixels forming an array of light emitting devices may be defective. The pixels may be defective because of improper formation, contamination, or other defects. Commonly, if the defect rate is too high, the entire display may be discarded.
Thus, there is a need for ways to make displays in a more economical fashion.